Dataset Information

Human coronaviruses OC43 and HKU1 bind to 9-O-acetylated sialic acids via a conserved receptor-binding site in spike protein domain A.

ABSTRACT: Human betacoronaviruses OC43 and HKU1 are endemic respiratory pathogens and, while related, originated from independent zoonotic introductions. OC43 is in fact a host-range variant of the species Betacoronavirus-1, and more closely related to bovine coronavirus (BCoV)-its presumptive ancestor-and porcine hemagglutinating encephalomyelitis virus (PHEV). The ?1-coronaviruses (?1CoVs) and HKU1 employ glycan-based receptors carrying 9-O-acetylated sialic acid (9-O-Ac-Sia). Receptor binding is mediated by spike protein S, the main determinant of coronavirus host specificity. For BCoV, a crystal structure for the receptor-binding domain S1A is available and for HKU1 a cryoelectron microscopy structure of the complete S ectodomain. However, the location of the receptor-binding site (RBS), arguably the single-most important piece of information, is unknown. Here we solved the 3.0-Å crystal structure of PHEV S1A We then took a comparative structural analysis approach to map the ?1CoV S RBS, using the general design of 9-O-Ac-Sia-binding sites as blueprint, backed-up by automated ligand docking, structure-guided mutagenesis of OC43, BCoV, and PHEV S1A, and infectivity assays with BCoV-S-pseudotyped vesicular stomatitis viruses. The RBS is not exclusive to OC43 and related animal viruses, but is apparently conserved and functional also in HKU1 S1A The binding affinity of the HKU1 S RBS toward short sialoglycans is significantly lower than that of OC43, which we attribute to differences in local architecture and accessibility, and which may be indicative for differences between the two viruses in receptor fine-specificity. Our findings challenge reports that would map the OC43 RBS elsewhere in S1A and that of HKU1 in domain S1B.

SUBMITTER: Hulswit RJG

PROVIDER: S-EPMC6377473 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Human coronaviruses OC43 and HKU1 bind to 9-O-acetylated sialic acids via a conserved receptor-binding site in spike protein domain A.

Hulswit Ruben J G RJG Lang Yifei Y Bakkers Mark J G MJG Li Wentao W Li Zeshi Z Schouten Arie A Ophorst Bram B van Kuppeveld Frank J M FJM Boons Geert-Jan GJ Bosch Berend-Jan BJ Huizinga Eric G EG de Groot Raoul J RJ

Proceedings of the National Academy of Sciences of the United States of America 20190124 7

Human betacoronaviruses OC43 and HKU1 are endemic respiratory pathogens and, while related, originated from independent zoonotic introductions. OC43 is in fact a host-range variant of the species Betacoronavirus-1, and more closely related to bovine coronavirus (BCoV)-its presumptive ancestor-and porcine hemagglutinating encephalomyelitis virus (PHEV). The β1-coronaviruses (β1CoVs) and HKU1 employ glycan-based receptors carrying 9-O-acetylated sialic acid (9-O-Ac-Sia). Recep ...[more]

PMID: 30679277

Similar Datasets

Project description:UnlabelledHuman coronavirus (hCoV) HKU1 is one of six hCoVs identified to date and the only one with an unidentified cellular receptor. hCoV-HKU1 encodes a hemagglutinin-esterase (HE) protein that is unique to the group a betacoronaviruses (group 2a). The function of HKU1-HE remains largely undetermined. In this study, we examined binding of the S1 domain of hCoV-HKU1 spike to a panel of cells and found that the S1 could specifically bind on the cell surface of a human rhabdomyosarcoma cell line, RD. Pretreatment of RD cells with neuraminidase (NA) and trypsin greatly reduced the binding, suggesting that the binding was mediated by sialic acids on glycoproteins. However, unlike other group 2a CoVs, e.g., hCoV-OC43, for which 9-O-acetylated sialic acid (9-O-Ac-Sia) serves as a receptor determinant, HKU1-S1 bound with neither 9-O-Ac-Sia-containing glycoprotein(s) nor rat and mouse erythrocytes. Nonetheless, the HKU1-HE was similar to OC43-HE, also possessed sialate-O-acetylesterase activity, and acted as a receptor-destroying enzyme (RDE) capable of eliminating the binding of HKU1-S1 to RD cells, whereas the O-acetylesterase-inactive HKU1-HE mutant lost this capacity. Using primary human ciliated airway epithelial (HAE) cell cultures, the only in vitro replication model for hCoV-HKU1 infection, we confirmed that pretreatment of HAE cells with HE but not the enzymatically inactive mutant blocked hCoV-HKU1 infection. These results demonstrate that hCoV-HKU1 exploits O-Ac-Sia as a cellular attachment receptor determinant to initiate the infection of host cells and that its HE protein possesses the corresponding sialate-O-acetylesterase RDE activity.ImportanceHuman coronaviruses (hCoV) are important human respiratory pathogens. Among the six hCoVs identified to date, only hCoV-HKU1 has no defined cellular receptor. It is also unclear whether hemagglutinin-esterase (HE) protein plays a role in viral entry. In this study, we found that, similarly to other members of the group 2a CoVs, sialic acid moieties on glycoproteins are critical receptor determinants for the hCoV-HKU1 infection. Interestingly, the virus seems to employ a type of sialic acid different from those employed by other group 2a CoVs. In addition, we determined that the HKU1-HE protein is an O-acetylesterase and acts as a receptor-destroying enzyme (RDE) for hCoV-HKU1. This is the first study to demonstrate that hCoV-HKU1 uses certain types of O-acetylated sialic acid residues on glycoproteins to initiate the infection of host cells and that the HKU1-HE protein possesses sialate-O-acetylesterase RDE activity.

Dataset Information

Human coronaviruses OC43 and HKU1 bind to 9-O-acetylated sialic acids via a conserved receptor-binding site in spike protein domain A.

Publications

Human coronaviruses OC43 and HKU1 bind to 9-<i>O</i>-acetylated sialic acids via a conserved receptor-binding site in spike protein domain A.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets